From ce74d76262d487e8b75719f017957b12a941061f Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Wed, 25 Dec 2024 11:05:27 +0100
Subject: [PATCH] cli: better runtime support for ESM dependencies in tests

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 packages/cli/config/jestCachingModuleLoader.js | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/packages/cli/config/jestCachingModuleLoader.js b/packages/cli/config/jestCachingModuleLoader.js
index 95c6212123..3b7740a4f7 100644
--- a/packages/cli/config/jestCachingModuleLoader.js
+++ b/packages/cli/config/jestCachingModuleLoader.js
@@ -33,4 +33,22 @@ module.exports = class CachingJestRuntime extends JestRuntime {
     }
     return script;
   }
+
+  // Notes(Rugvip): As far as I can tell this is the best we can currently do
+  // for runtime ESM support in Jest. What the below logic effectively does is
+  // to only allow packages to be loaded as ESM if all imports of that package
+  // are done in an ESM compatible way, as in either from ESM code or with a
+  // dynamic import.
+  cjsModules = new Set();
+  _resolveCjsModule(...args) {
+    const path = super._resolveCjsModule(...args);
+    this.cjsModules.add(path);
+    return path;
+  }
+  unstable_shouldLoadAsEsm(path, ...restArgs) {
+    if (this.cjsModules.has(path)) {
+      return false;
+    }
+    return super.unstable_shouldLoadAsEsm(path, ...restArgs);
+  }
 };